Interaction of octaethylene glycol n-dodecyl monoether with dioctadecyldimethylammonium bromide and chloride vesicles

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dc.contributor.authorBarreleiro, PCA
dc.contributor.authorOlofsson, G.
dc.contributor.authorBrown, W.
dc.contributor.authorEdwards, K.
dc.contributor.authorBonassi, N. M.
dc.contributor.authorFeitosa, E.
dc.contributor.institutionLund Univ
dc.contributor.institutionUniv Uppsala
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T14:02:17Z
dc.date.available2014-05-20T14:02:17Z
dc.date.issued2002-02-19
dc.description.abstractSeveral different methods were used to investigate the vesicle-to-micelle transition induced by the addition of the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) to spontaneously formed vesicle dispersions of dioctadecyldimethylammonium bromide and chloride (DODAX, X = Cl- and Br-). Dynamic light scattering reveals that fast mode micelles are formed upon addition of C12E6. The micellar mode becomes progressively dominant as the C12E8/DODAX molar ratio (R) is increased until the vesicle-to-micelle transition is complete. Turbidity, calorimetry, fluorescence quantum yield, and anisotropy measurements indicate two critical compositions: the first, R-sat, when the vesicle bilayer is saturated with C12E8 and the second, R-sol, which corresponds to the complete vesicle-to-micelle transition. Below R-sat the vesicles swell due to incorporation of the surfactant into the vesicle bilayer, and above R-sat mixed micelles and bilayer structures coexist, the determined R-sat and R-sol range from 0 to 1 and 4 to 6, respectively, depending on the surfactant counterion and the experimental method used. Cryo-transmission electron microscopy micrographs show that when R approximate to 4, micelles coexist with extended bilayer fragments. In pure DODAX (1.0 mM) dispersions, unilamellar vesicles are observed. According to the DSC results, C12E8 lowers the gel-to-liquid crystalline transition temperature, T-m, of DODAX and broadens the main transition peak which disappears around R approximate to 5 and 6 for DODAC and DODAB, respectively.en
dc.description.affiliationLund Univ, Ctr Chem & Chem Engn, S-22100 Lund, Sweden
dc.description.affiliationUniv Uppsala, Dept Phys Chem, S-75121 Uppsala, Sweden
dc.description.affiliationUNESP, IBILCE, Dept Phys, BR-15054000 Sao Jose do Rio Preto, SP, Brazil
dc.description.affiliationUnespUNESP, IBILCE, Dept Phys, BR-15054000 Sao Jose do Rio Preto, SP, Brazil
dc.format.extent1024-1029
dc.identifierhttp://dx.doi.org/10.1021/la010876z
dc.identifier.citationLangmuir. Washington: Amer Chemical Soc, v. 18, n. 4, p. 1024-1029, 2002.
dc.identifier.doi10.1021/la010876z
dc.identifier.issn0743-7463
dc.identifier.urihttp://hdl.handle.net/11449/21949
dc.identifier.wosWOS:000174009300014
dc.language.isoeng
dc.publisherAmer Chemical Soc
dc.relation.ispartofLangmuir
dc.relation.ispartofjcr3.789
dc.relation.ispartofsjr1,479
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.titleInteraction of octaethylene glycol n-dodecyl monoether with dioctadecyldimethylammonium bromide and chloride vesiclesen
dc.typeArtigo
dcterms.licensehttp://pubs.acs.org/paragonplus/copyright/jpa_form_a.pdf
dcterms.rightsHolderAmer Chemical Soc
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Biociências Letras e Ciências Exatas, São José do Rio Pretopt

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